Conventionally, a method for measuring luminance of each pixel in a light-emitting display panel from image data obtained by capturing an image of the light-emitting display panel in which the pixels produce a luminescence according to a predetermined display pattern is known as a method for inspecting a luminescent state of the light-emitting display panel. Here, the light-emitting display panel is a display panel in which the pixels are two-dimensionally arranged, such as a liquid-crystal display panel, a plasma display panel, and an organic electroluminescence (EL) display panel.
For example, PTL 1 discloses a method for measuring luminance of each pixel, by calculating a cumulative sum of luminance values in a measurement region determined by a resolution of a camera and the number of pixels that simultaneously emit light from among the pixels included in a display panel, for each of the measurement regions.
According to this method, since the luminance of one pixel is measured by calculating a cumulative sum of the luminance values of light receiving elements included in the measurement region on which the images of the pixels are to be formed, the luminance of each of the pixels can be measured without aligning the pixels with the light receiving elements with accuracy.
Furthermore, PTL 2 discloses a method for measuring luminance of each pixel with higher accuracy by calculating a cumulative sum of luminance values excluding (i) a luminance value of a light receiving element on which an image of a black stripe portion in a display panel is to be formed and (ii) a luminance value of a light receiving element on which images of pixels are to be formed.